When a lethal flu virus ravages the global population, Abby Grant (Julie Graham) begins a search for her missing son, and soon becomes the leader of a small group of survivors trying to live in a world thrown into chaos. As Abby follows clues to her boy's whereabouts, her band must compete for scarce resources with violent gangs, a strange cult leader and more. This remake of the 1970s British TV drama of the same name co-stars Max Beesley.